Psalms 51:14

Psalms 51:14. Deliver me from bloodguiltiness, O God, thou God of my salvation:

He called his sin by its right name. He knew that he had really been the murderer of Uriah, so he confesses his guilt in all its hideousness: "Deliver me from bloods (see marginal reading), O God, thou God of my salvation." It is remarkable that, when David confesses his sin in the strongest language that he can use, he at the same time lays hold upon God with the boldest faith that he can exercise. So, the deeper the sense of sin in us is, the stronger can the grace of God make our faith to be.

Psalms 51:14. And my tongue shall sing aloud of thy righteousness.

Should not David have said, "My tongue shall sing aloud of thy mercy"? That would have been quite right, yet David knew that God had a way of bestowing his mercy in complete consistency with his righteousness; and this being the more singular part of divine forgiveness, the most astonishing wonder of all, he selects that, and says, "My tongue shall sing aloud of thy righteousness."